Edelbrock Pro-Flo 4 EFI Kit #35850 for Big-Block Chevy Rectangle Port engines. The EFI system comes complete with traditional 4150-Style single plane intake manifold and 35 Lb/Hr injectors capable of 550 HP with 58 p.s.i. fuel pressure. Included is plug and play single connection distributor designed to work specifically with Pro-Flo 4 and made in the USA fully terminated high-quality harness with clearly labeled connections to ensure a hassle-free installation. The new Pro-Flo 4 EFI systems feature all-new ECU with a faster processor, a water proof design and measures half the depth of the previous ECU. Also has an upgraded Bluetooth chip that is faster, more reliable and will not drop connection. Edelbrock added more features for the advanced tuner giving you control over air-fuel ratios, ignition curve, idle speed, acceleration fuel, coolant fans, Rev limiter. The key to the system is the exclusive E-Tuner 4 app with dyno developed base calibrations. The E-Tuner 4 app uses Bluetooth wireless connection to communicate with the ECU's self-learning capability to continually adjust the calibration to get the maximize performance. E-Tuner 4 features simple and easy to use setup wizard to help you get started as well as multiple dash displays so you can monitor your engines vitals. The exclusive Edelbrock E-Tuner 4 app is Free and Available for Android and IOS based smart phone or tablet.